Effect of aggregated silver nanoparticles on luminol chemiluminescence system and its analytical application

• For AgNPs’s catalysis on luminol CL system, aggregation was an important factor.
• The aggregated AgNPs’s effect characteristic was closely related to AgNPs’s sizes.
• Aggregation led to CL increase for 7 nm, decline for 15 nm and no change for 55 nm.
• Aggregated AgNPs’s effect is due to electron density’s change in conduction band.

We found that after silver nanoparticles (AgNPs) aggregated, its catalytic activity on luminol CL reaction obviously changed, and the change characteristic was closely related to the sizes of AgNPs. UV–visible spectra, X-ray photoelectron spectra, zeta potential and transmission electron microscopy studies were carried out to investigate the CL effect mechanism. The different CL responses of aggregated AgNPs with different size were suggested to be due to the two effects of quantum size and electron density in nanoparticle’s conduction bands, and which one played a major role. The poisonous organic contaminants such as anilines, could induce the aggregation of AgNPs, were observed to affect effectively the luminol–H2O2–7 nm and 15 nm AgNPs CL systems and were detectable by use of a flow injection method with the enhanced or inhibited CL detection.

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